1. Field of the Invention
This invention relates to variable color display devices.
2. Description of the Prior Art
A display device that can change color and selectively exhibit characters is described in my U.S. Pat. No. 4,086,514 entitled Variable Color Display Device and issued on Apr. 25, 1978. This display device includes display areas arranged in a suitable display font, such as well known 7-segment font, which may be selectively energized in groups to exhibit all known characters. Each display area includes three light emitting diodes for emitting light signals of respectively different primary colors which are blended within the display area to form a composite light signal. The color of the composite light signal can be controlled by varying the portions of the primary light signals.
The capability of a variable color display device to vary the color of its display areas over the entire spectrum has a drawback in that certain colors of the display areas may be similar to the color of the display background, thereby rendering the exhibited character difficult to recognize, particularly in imperfect viewing conditions. From an aesthetic aspect, small color differences between the display and background areas are likely to be displeasing and give an impression of instability.